GM-LG JV Ultium Cells to Mass-Produce LMR Prismatic Cells at Its Tennessee Plant — 33% More Energy Density Than LFP at Comparable Cost, Conversion Complete in 2028
On September 29, 2026, Ultium Cells, the battery joint venture between GM and LG Energy Solution, announced that it will upgrade its plant in Spring Hill, Tennessee, to mass-produce lithium manganese rich (LMR) prismatic battery cells. According to GM, if realized, Ultium Cells is expected to become the first manufacturer in the world to produce LMR cells commercially.
GM says it designed LMR to deliver 33% higher energy density than lithium iron phosphate (LFP), today's mainstream low-cost battery chemistry, at comparable cost.
What was announced
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01
Product
LMR prismatic cells for future GM EVs. Expected to be a world first in commercial production.
02
Performance target
33% more energy density than LFP, at cost comparable to LFP.
03
Schedule
Construction and equipment upgrades begin later in 2026, with completion expected in 2028.
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Jobs
500 new jobs, on top of the current workforce of 1,200.
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Investment
$1 billion by 2030 in total across the LMR conversion, ESS LFP cell production and plant improvements (Tennessee Department of Economic and Community Development).
According to the Tennessee Department of Economic and Community Development, the Spring Hill plant has also been producing LFP cells for ESS (stationary energy storage) for LG Energy Solution Vertech's customers since June 2026. Combined investment in the LMR conversion, ESS LFP production and plant improvements is expected to reach $1 billion by 2030.
How the three chemistries are divided up
LMR is a cathode family that uses more manganese and less nickel and cobalt. In GM's framing, high-nickel covers the top of the range, while LMR raises density within the same price band as LFP.
The two companies announced the Spring Hill plant in 2021 with more than $2.3 billion of investment and 1,300 jobs, then added a $275 million, 400-job expansion in 2022. Built as an EV cell plant, it is now turning into a site that makes ESS LFP and EV LMR cells on the same campus.
Battery selection for low-cost EVs: a price band that has been LFP-only may gain an option with higher density. But mass production starts only after the conversion is completed in 2028, and 33% at comparable cost is GM's design target, not a volume-production result
Materials sourcing: if LMR ramps up, demand for manganese-based cathode materials in North America will rise. Procurement teams looking to reduce dependence on nickel and cobalt gain another material to start evaluating
How plants are used: as plants making EV and ESS cells in multiple chemistries become more common, contracts with cell makers may shift away from single-product volume agreements tied to EV demand
